The invention discloses a big-data-based distributed power distribution network planning method. The method comprises: historical data are collected and arrangement to form a large database for convenient storage and searching; and a power distribution network is planned, data in the large database are invoked in real time, and then the power distribution network is planned and set reasonably. According to the invention, at a load analysis stage, an electricity consumption tendency of a user is dug, an electricity demand prediction model of the user is perfected, dynamic market information is obtained actively, and thus a foundation is laid for project design planning. At a project planning design stage, making of decisions of distributed power supply site selection and project scale construction in the distribution network is helped and the power generation efficiency is improved. At an equipment operation stage, an operation and maintenance way is effective changed to realize intelligent operation and maintenance. And at a data integration stage, data sharing at all links in the distribution network is realized, a scheduling and management department is assisted in making decisions, energy losses are reduced, and the working efficiency and the energy utilization rate are improved.